Adjusting device for the tuning mechanism of radio receivers



Nov. 30 1943.

. H. W. RUBlNSTElN ADJUSTING DEVICE FOR THE TUNING MECHANISM OF RADIO RECEIVERS Filed Dec. 15, 1941 BY, v ATTORNEY.

Patented Nov. 30, 1943 ADJUSTING DEVICE FOR THE TUNING MECHANISM OF RADIO RECEIVERS Harry W. Rubinstein, Milwaukee, Wis., assignor to Globe-Union Inc., Milwaukee, Wis., a corporation of Delaware Application December 13, 1941, Serial No. 422,812

6 Claims. (01. 308-22) This invention relates in general to radio receivers, and more particularly to means for adjusting the tuning mechanism of such receivers. Conventional radio receivers are provided with a knob on the control panel which is afiixed to the outer end of the shaft, usually of round stock, the shaft being in turn geared, in many instances, by a metallic motion transmission train to the rotatable shaft of a variable condenser, so that by turning the knob the capacity in the tuning circuits will be varied to bring the receiver into resonance with the station which it is desired to receive.

The present emergency has drastically curtailed the amount of metal available for purposes other than those directly or indirectly connected with the national defense so that the problem of supplying the demand for radio receivers is acute, particularly so because to construct them along standard lines would require more metal than may be allotted to the radio industry.

The present invention provides an adjusting device for the tuning mechanism of a radio receiver which uses only a fraction of the metal previously required for this purpose, and which will make it practical to take the available supply of metal for these parts for this industry and so utilize it as to substantially supply the domestic demand for radio receivers.

In carrying out the present invention the use of a round shaft with its excess metal is avoided,

a shaft of flat stock having very much less metal than one of round stock being employed. The shaft is mounted in a novel Way and with a minimum number of parts composed of a small amount of metal, and yet is rigidly and securely mounted for rotation, and the very elements that go into the mounting of the shaft are also employed as elements of the drive between the knob and shaft and the operating shaft of the variable condenser of the tuning mechanism. And in lieu of providing gearing or other metal parts as the motion transmission train between the control shaft and the variable condenser, a flexible motion transmission element in the form of a cord of textile material, or the like, is employed. Along with these advantages, the present invention is flexible in its nature, in that its parts may be interchanged or reversed to adapt the device to the requirements of different receiver designs.

Other objects and advantages reside in certain novel features of the construction, arrangement, and combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawing forming a part of this specification, and in which:

Figure 1 is a fragmentary view, partly in transverse, vertical cross section and partly in elevation, illustrating an adjusting device for the tuning mechanism of radio receivers embodying the present invention;

Figure 2 is an enlarged sectional view showing the mounting for the control shaft of the device illustrated in Figure 1 and the way in which the mounting is combined in the drive or the motion' transmission train between the control shaft and the variable condenser;

Figures 3 and 4 are detail views in side and front elevations, respectively, of the mounting bracket embodied in the adjusting device of the present invention;

Figure 5 is a view partly in side elevation and partly in central, vertical, longitudinal cross section, illustrating the cartridge-type bearing sleeve employed for the control shaft and as an element of the motion transmission train.

Figures 6 and '7 are views in end elevation of the cartridge-type bearing sleeve shown in Figure 5, Figure 6 looking at the front end and Figure 7 at the rear end thereof.

Figures 8 and 9 are detail views of the two washers which are employed at one end of the bearing sleeve to hold the same against axial displacement;

Figure 10 is a view partly in section and partly in elevation but showing the mounting bracket Figure 12 is a fragmentary view in end elevation looking toward the right hand side of Figur 11. Referring to the drawing, and more particu-' larly to Figures 1 and 2, the numeral 1 designates the chassis of a radio receiver supported in asuitable casing or cabinet (not shown) but including as usual a control panel 2, the control panel 2 being disposed in front of and in spaced relation to the front plate 3 of the chassis. The

chassis supports a bracket 4, which in turn is part of the variable condensers 5, usually of the interleaved type, with the overlap of the'plates j of the condenser controlled by the rotative ad- 7 justment of the control shaft 6 affixed to the adjustable plates of the variable condenser and provided with a pointer or indicator 8 at its outer end which travels over the usual dial to facilitate selection of the station to be received. A pulley Ii] is fixed to the shaft 6 to receive the drive whereby the condenser may be adjustable to vary the capacity in the tuning circuits and consequently bring the receiver into resonance with the station that is to be selected.

The adjusting mechanism for the tuning mechanism described, and which embodies the present invention, comprises a U-shaped bracket, designated generally at II. The bracket II has a body portion I2 and integral legs I3. The legs I3 are provided with flanges or attaching lugs I4 adapted to fit flush against the vertical plate 3 of the chassis and to be suitably secured thereto by suitable fastening devices. The body portion I2 of the bracket is provided vw'th a bearing opening I5 which is alined with a similar bearing opening I6 provided in the chassis plate 3. A cartridge-type bearing bushing, designated generally at IT, is provided and comprises a cylindrical body portion I8 provided at one end with an integral end wall I9 united to the body portion of the cartridge by means of a crimp or flange 20. The end wall I9 is provided with a transverse slot 2|. At the end of the bearing bushing opposite the wall I9 its cylindrical body portion is provided with diametrically opposite integral securing tabs 22. The bushing is assembled with the chassis plate 3 and bearing bracket I I in the manner clearly illustrated in Figure 2, and in the assembly the flange at the closed endof the bushing rotatably abuts the margin of the bearing opening I6 of the chassis plate 3. The opposite end of the bushing projects beyond the bearing opening I5 of the body portion I2 of the bracket. In this way the cartridge-type bushing is supported at longitudinally spaced points for rotation so that it is secure and stable sup- .port is had, the bushing being constrained to rotate about a fixed axis. Furthermore, the flange 20 of the bushing constrains it against axial movement or displacement in one direction. To maintain the bushing against axial displacement in the opposite direction, suitable abutment means, in this case a washer, is combined with the end of the bushing II which projects beyond the body portion I2 of the bracket II. In the construction illustrated, this washer or abutment means comprises a round spring washer or annulus 23 which bears against the margin of the opening I5 in the body portion I2 of the bracket H, and a disc-like washer 24 also fitted over the projecting end of the bushing and abutting the outer face of the washer 23. The washer 24 is formed with a transverse slot 25 shown to advantage in Figure 9 so that in the assembly the securing tabs 22 may be extended through the ends of the slot 25 and bent or clinched over against the portions of the washer 24 lying beyond the ends of the slot 25, the spring or bowed washer 23 providing a spring take-up means in this assembly. Also the tabs 22 provide seats or keepers designed to have latching engagement with the control shafts, as will be presently described.

A control shaft 25 is provided and is con-,- structed of flat stock which may be stamped from a flat strip of stiflly resilient metal of suitable gauge and then cut into sections of appropriate length and shape. The inner end of this shaft is a embled th he ari ush n 8. The

' plate.

outer end thereof projects outwardly through an opening 2' in the panel 2 of the cabinet of the receiver, the outer end being slotted, as at 21, or otherwise suitably fashioned to adapt it to be attached to a control knob 28. The inner end of the shaft 26 is provided with a longitudinal slot 29, which extends for a considerable portion of the length of the shaft and out through the inner end thereof. The portion of the shaft in which the slot 29 is formed is of reduced width so that shoulders 30 are presented at the juncture of the reduced portion and the main portion of the shaft. Near the end of the shaft through which the slot 29 extends, the slot is widened out or flared. With this construction the inner end of the shaft is provided with spring arms 3 I, and the inner extremities of these spring arms 3I are formed with beveled latching projections 32 designed to have actual engagement with the bent-over tabs 22 to releasably secure the shaft against axial displacement when the shaft is assembled with the bearing bushing. The extension of the flat shaft through the correspondingly formed rectangular slot 2| in the end wall I9 and the engagement of its latching projections with the flanged-over tabs 22, rotatably couples or keys the shaft to the bearing bushing so that when the shaft is turned the bushing is turned.

For transmitting the motion from the bushing I! to the pulley II], a flexible motion transmission element or cord 35 is provided. This cord 35 may be endless and may be wrapped around the bushing II, as indicated at 36, and either Wrapped or just reeved around the pulley II), as conditions may require.

With this construction, when the knob 28 is turned, the shaft 26 and bushing II are also turned and the motion of the bushing I1 is transmitted through the cord 35 to the pulley I!) so that the variable condenser is adjusted to bring the radio receiver into resonance with the station to be selected.

In the form .of the invention shown in Figure 10, the bracket II, bushing II, shaft 26, flexible motion transmission element and cord 35, are all provided as before. However, the bracket II is placed on the outside of the chassis plate 3, and the crimp or flange 2I of the sleeve I'I engages the margin of the bearing opening I5 of the bracket instead of the margin of the bearing opening I6 of the chassis plate. Furthermore, the washers 23 and 24 are disposed adjacent the margin of the bearing opening I6 of the chassis In all other respects the two constructions are identical.

In the form of the invention shown in Figures 11 and 12, the bracket I I, cartridge-type bearing bushing I1, and shaft 26, are provided as before. However, the washer 24 is omitted and its place is taken by the web 31 of a driving pulley 38. The driving pulley 38 may be a sheet metal stamping and it is clamped up against the washer by clinching the tabs 22 thereagainst. The web 31 of the driving pulley 38 is provided at its center with a slot 25 similar in configuration to the slot 25 of the washer 24. In this form of the invention the flexible element 35 is wrapped in the peripheral groove of the driving pulley 38.

While I have shown and described several constructions in which the invention may be advantageously embodied, it is to be understood that the constructions shown have been selected merey for. the purpose of illustration or example, and that various changes in the size, shape, and arrangement of the parts may be made without departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

1. An adjusting device for the tuning mechanism of radio receivers including a chassis having a bearing opening, a U-shaped bracket having its legs secured to the chassi and having its body portion provided with a bearing opening coaxial with and in spaced relation to the bearing opening of the chassis, a bearing bushing rotatably supported in said bearing openings, means at one end of the bearing bushing engageable with the margin of one of the bearings and preventing axial movement of the bearing bushing in one direction, the opposite end of the bearing bushing projecting beyond the other end of the bearing opening, a driving pulley mounted on the projecting end of the bearing bushing, and means for securing the driving pulley to the bearing bushing and preventing axial displacement of the bearing bushing in the opposite direction.

2. An adjusting device for the tuning mechanism of radio receivers including a chassis plate having a bearing opening, a bracket supported on the chassis plate with its body portion in spaced relation thereto, said body portion having a bearing opening therein coaxial with the hearing opening in the chassis plate, a bearing bushing having its body portion rotatably supported at longitudinally spaced points in said bearing openings, means at the ends of the bushing engageable with the margins of said openings to hold the bushing against axial displacement while providing for free rotation thereof in its bearing openings, and a control shaft of flat stock having a portion supported in and rotatively coupled to the bushing and having a latching projection for releasably securing the shaft against axial displacement relative to the bushing, said bushing also being adapted, when rotated by said control shaft, to drive a motion transmission element,

3. An adjusting device for the tuning mechanism of radio receivers including a chassis plate having a bearing opening, a bracket supported on the chassis plate with its body portion in spaced relation thereto, said body portion having a bearing opening therein coaxial with the bearing opening of the chassis plate, a cartridge-type bearing bushing having the outer periphery of its body portion rotatably supported at longitudinally spaced points in said bearing openings and having a closed and flanged end, with the flange of aid closed end rotatably abutting the margin of one of said bearing openings, the closed end of the bushing having a transverse slot, the opposite "ends of the body portion of the bearing bushing projecting beyond the other bearing opening, means mounted on the projecting end of the body portion of the bushing and rotatably abutting the margin of the adjacent bearing opening, securing tabs. integral with the body portion, of the bushing and clinched against said means whereby the bushing is held against axial displacement although free to rotate in its bearing openings, a control shaft of flat stock and having its inner end reduced and inserted into the bushing through said transverse slot to rotatively couple the shaft to the bushing, said shaft having latching projection engageable with said tabs for releasably securing the shaft against axial displacement relative to the bushing.

4. In combination with a support having a bearing opening, an adjusting device comprising a bracket mounted on the support with its body portion in spaced relation thereto, said body portion having a bearing opening therein coaxial with the bearing opening in the support, a bearing bushing having its body portion rotatably supported at longitudinally spaced points in said bearing openings, means at the ends of said bushing engageable with the margins of said openings to hold the bushing against axial displacement while providing for free rotation thereof in said bearing openings, and a control shaft of flat stock rotatively coupled to the bushing and having a latching projection for releasably securing the shaft against axial displacement relative to the bushing, there being unobstructed access to the outer peripheryof the bearing bushing intermediate its spaced points of support whereby such portion of the outer periphery of the bearing bushing is adapted to have driving engagement with a flexible motion transmission element.

5. In combination with a support having a bearing opening, a U-shaped bracket having its legs attached to the support and having its body portion provided with a bearing opening coaxial with and in spaced relation to the bearing opening of the support, a bearing bushing rotatably supported in said bearing openings and having means at its ends engageable with the margins of said openings to hold the bushing against axial displacement while providing for free rotation thereof in said bearing openings, and a control shaft of flat stock rotatively coupled to the bushing and having a latching projection for releasably securing the shaft against axial displacement relative to the bushing.

6. In combination with a support having a bearing opening, a U-shaped bracket having its legs attached to the support and having its body portion provided with a bearing opening coaxial with and in paced relation to the bearing opening of the support, a cartridge-type bearing bushing having its body portion rotatably supported in said bearing openings and having one end closed and flanged, with the flange of said closed end rotatively abutting the margin of one of said bearing openings, the closed end of the bushing having a transverse slot, the opposite end of the bushing projecting beyond the bearing opening spaced from that engaged with the flange, washer means on the projecting end of the bearing-bushing and abutting the margin of the adjacent bearing opening, securing tabs integral with the bearing bushing and clinched over said washer means to maintain the parts in assembly whereby the bushing is held against axial movement although free to rotate in its bearing openings, and a control shaft having its inner end reduced and of fiat stock, said inner end of the shaft being inserted in the bushing through said transverse slot, the inner end of the shaft being slotted to provide spring arms, said spring arms having beveled latching projections interengageable with the tabs for releasably securing said shaft against axial displacement.

HARRY W. RUBINS'I'EIN. 

